G04 Encephalitis, myelitis and encephalomyelitis

⚠ Non-Billable ICD-10-CM 2026
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The ICD-10-CM code for Encephalitis, myelitis and encephalomyelitis is G04 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Section
G00-G09: Inflammatory diseases of the central nervous system (G00-G09)
Category G04
19 codes (14 billable)
FY2026 Status
Stable since FY2024
Includes
  • acute ascending myelitis
  • meningoencephalitis
  • meningomyelitis
Excludes1
Not coded here. These conditions should NOT be coded together with G04.
  • encephalopathy NOS (G93.40)
Excludes2
Not included here. These conditions are coded elsewhere but may be coded together if applicable.
  • acute transverse myelitis (G37.3)
  • alcoholic encephalopathy (G31.2)
  • multiple sclerosis (G35-)
  • myalgic encephalomyelitis (G93.32)
  • subacute necrotizing myelitis (G37.4)
  • toxic encephalitis (G92.8)
  • toxic encephalopathy (G92.8)

Official Coding Guidelines

Dominant/nondominant side (TOC entry)

a. Dominant/nondominant side ................................................................................................. 45

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.6.a
Pain - Category G89 (TOC entry)

b. Pain - Category G89.............................................................................................................. 45

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.6.b

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

Related Codes

More Specific Codes

G04.0 Acute disseminated encephalitis and encephalomyelitis (ADEM) G04.00 Acute disseminated encephalitis and encephalomyelitis, unspecified G04.01 Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) G04.02 Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis G04.1 Tropical spastic paraplegia G04.2 Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified G04.3 Acute necrotizing hemorrhagic encephalopathy G04.30 Acute necrotizing hemorrhagic encephalopathy, unspecified G04.31 Postinfectious acute necrotizing hemorrhagic encephalopathy G04.32 Postimmunization acute necrotizing hemorrhagic encephalopathy G04.39 Other acute necrotizing hemorrhagic encephalopathy G04.8 Other encephalitis, myelitis and encephalomyelitis G04.81 Other encephalitis and encephalomyelitis G04.82 Acute flaccid myelitis G04.89 Other myelitis G04.9 Encephalitis, myelitis and encephalomyelitis, unspecified G04.90 Encephalitis and encephalomyelitis, unspecified G04.91 Myelitis, unspecified

Related Codes in G04

G04.0 Acute disseminated encephalitis and encephalomyelitis (ADEM) G04.00 Acute disseminated encephalitis and encephalomyelitis, unspecified G04.01 Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) G04.02 Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis G04.1 Tropical spastic paraplegia G04.2 Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified G04.3 Acute necrotizing hemorrhagic encephalopathy G04.30 Acute necrotizing hemorrhagic encephalopathy, unspecified G04.31 Postinfectious acute necrotizing hemorrhagic encephalopathy G04.32 Postimmunization acute necrotizing hemorrhagic encephalopathy G04.39 Other acute necrotizing hemorrhagic encephalopathy G04.8 Other encephalitis, myelitis and encephalomyelitis G04.81 Other encephalitis and encephalomyelitis G04.82 Acute flaccid myelitis G04.89 Other myelitis G04.9 Encephalitis, myelitis and encephalomyelitis, unspecified G04.90 Encephalitis and encephalomyelitis, unspecified G04.91 Myelitis, unspecified
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Reviewed by Prajwal Shrestha, CPC, CRC
Certified Professional Coder (CPC) and Certified Risk Adjustment Coder (CRC) · AAPC Member ID 01997614 · About · Editorial policy · Content last reviewed: 2025-10-01

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